Induction of the Differentiation of HL-60 Promyelocytic Leukemia Cells by l-Ascorbic Acid

The present study was undertaken to examine the effect of l-ascorbic acid (LAA) on the growth of HL-60 promyelocytic leukemia cells, besides induction of apoptosis. LAA (≥10^-4?M) was found to markedly inhibit the proliferation of HL-60 in liquid culture and clonogenicity in semisolid culture. Moreover, LAA-treated HL-60 showed activity to produce chemiluminescence and expressed CD 66b cell surface antigens, indicating that LAA induces the differentiation of HL-60 mainly into granulocytes. The results are supported by morphological changes of LAA-treated HL-60 into segmented neutrophils. Therefore, the inhibitory effect of LAA on the growth of HL-60 cells seems to arise from the induction of differentiation. To assess the potential role of LAA, cells were exposed to oxygen radical scavengers in the absence or presence of LAA. Catalase abolished and superoxide dismutase promoted LAA-induced differentiation of HL-60. Thus, H²O² produced as a result of LAA treatment seems to play a major role in induction of HL-60 differentiation.     

A Relationship Between Replication Protein A and Occurrence and Prognosis of Esophageal Carcinoma

Esophageal carcinoma (EC) is an aggressive and the third most common cancer of the digestive tract with poor prognosis. Replication protein A (RPA) is critically required for DNA replication and its elevated expression has been observed in many malignant tumors. In this study, we investigated the expression of RPA1 and RPA2, subunits of RPA, and assessed their prognostic value in EC patients. We analyzed immunohistochemically the expression of RPA1 and RPA2 proteins in 48 EC resection specimens in relation with clinicopathological parameters and survival. We observed a significant elevated (P < 0.001) RPA1 and RPA2 expressions (labeling index) in the tumor than adjacent non-tumor tissues. In addition, both RPA1 and RPA2 labeling index in lymph node metastasis patients was significantly higher (both P = 0.000) than patients without lymph node metastasis. However, RPA1 and RPA2 labeling index in early stage was significantly lower (P = 0.000 and P = 0.002, respectively) than that of late stage EC patients. Importantly, patient’s survival at early stage was significantly higher (P = 0.016) than late stage EC and lymph node metastasis and RPA1 expression was associated with adverse patient’s outcome in multivariate analysis (P < 0.05 and P < 0.00, respectively). In conclusion, RPA1 could be a useful prognostic indicator in patients with esophageal carcinoma and might be a future attractive therapeutic target for regulation by tumor suppressors.     

Endonasal Endoscopic Treatment of Recurrent Dacryocystitis

This report assessed clinical conditions leading to recurrent dacryocystitis and success rates of its treatment by endonasal endoscopic dacryocystorhinostomy. Forty-eight patients with recurrent dacryocystitis underwent endonasal endoscopic surgery and were followed up for at least 6 months. High bone windows, small bone window openings, small lacrimal sac stomas, scar tissues, and organic diseases of the nasal cavity led to fistula closure. Out of 48 patients, 45 (93.8 %) patients were cured by endonasal endoscopic surgery. Endonasal endoscopic dacryocystorhinostomy is beneficial for recurrent dacryocystitis.     

Hemodynamic impacts of various types of stenosis in the left coronary artery bifurcation: A patient-specific analysis

This study investigates the hemodynamic changes to various types of coronary stenosis in the left coronary artery bifurcation, based on a patient-specific analysis. Twenty two patients with left coronary artery disease were included in this study. All stenoses involving the left coronary artery bifurcation were classified into four types, according to their locations: A) left circumflex (LCx) and left anterior descending (LAD), B) LCx only, C) left main stem only, and D) LAD only. Computational fluid dynamics (CFD) was performed to analyze the flow and wall shear stress (WSS) changes in all reconstructed left coronary geometries. Our results showed that the flow velocity and WSS were significantly increased at stenotic locations. High WSS was found at >70% lumen stenosis, which ranged from 2.5 Pa to 3.5 Pa. This study demonstrates that in patients with more than 50% stenosis in the left coronary artery bifurcation, WSS plays an important role in providing information about the extent of coronary atherosclerosis in the left coronary artery branch.     

Suppression of Grb2 expression improved hepatic steatosis, oxidative stress, and apoptosis induced by palmitic acid in vitro partly through insulin signaling alteration

In this study, we aimed to study the role of growth factor receptor-bound protein 2 (Grb2) in palmitic acid-induced steatosis and other “fatty liver” symptoms in vitro. HepG2 cells, with or without stably suppressed Grb2 expression, were incubated with palmitic acid for 24 h to induce typical clinical “fatty liver” features, including steatosis, impaired glucose metabolism, oxidative stress, and apoptosis. MTT and Oil Red O assays were applied to test cell viability and fat deposition, respectively. Glucose uptake assay was used to evaluate the glucose utilization of cells. Quantitative polymerase chain reaction and Western blot were used to measure expressional changes of key markers of insulin signaling, lipid/glucose metabolism, oxidative stress, and apoptosis. After 24-h palmitic acid induction, increased fat accumulation, reduced glucose uptake, impaired insulin signaling, enhanced oxidative stress, and increased apoptosis were observed in HepG2 cells. Suppression of Grb2 in HepG2 significantly reduced fat accumulation, improved glucose metabolism, ameliorated oxidative stress, and restored the activity of insulin receptor substrate-1/Akt and MEK/ERK pathways. In addition, Grb2 deficiency attenuated hepatic apoptosis shown by reduced activation of caspase-3 and fluorescent staining. Modulation of Bcl-2 and Bak1 also contributed to reduced apoptosis. In conclusion, suppression of Grb2 expression in HepG2 cells improved hepatic steatosis, glucose metabolism, oxidative stress, and apoptosis induced by palmitic acid incubation partly though modulating the insulin signaling pathway.     

Silencing of cytosolic NADP+-dependent isocitrate dehydrogenase by small interfering RNA enhances the sensitivity of HeLa cells toward staurosporine

Staurosporine induces the production of reactive oxygen species, which play an important causative role in apoptotic cell death. Recently, it was demonstrated that the control of cellular redox balance and the defense against oxidative damage is one of the primary functions of cytosolic NADP⁺-dependent isocitrate dehydrogenase (IDPc) by supplying NADPH for antioxidant systems. The present report shows that silencing of IDPc expression in HeLa cells greatly enhances apoptosis induced by staurosporine. Transfection of HeLa cells with an IDPc small interfering RNA (siRNA) markedly decreased activity of IDPc, enhancing the susceptibility of staurosporine-induced apoptosis reflected by DNA fragmentation, cellular redox status and the modulation of apoptotic marker proteins. These results indicate that IDPc may play an important role in regulating the apoptosis induced by staurosporine and the sensitizing effect of IDPc siRNA on the apoptotic cell death of HeLa cells offers the possibility of developing a modifier of cancer chemotherapy.